I've had some success unit testing JavaScript functions using JInt in a Test Project in Visual Studio.  Many JavaScript functions just return values or manipulate internal variables, but MOST JavaScript deals with client-side script interaction with a browser document in HTML.  Just look at http://www.w3schools.com/js/js_examples.asp

So.  Is it possible in JInt?  There sure aren't any easily-accessible examples on this site showing how to getElementById.  It would be so cool if I could see HTML changes made by JavaScript without running IIS or Cassini.

I have done that 2 years ago and it was working fine. Using envJs, with some work inside envjs to make it compatible with Jint.